DNA is approximately 2.2 m long thread which has to be adjusted in a microscopic nucleus so DNA must be in a supercoiled form to be present in the nucleus and this supercoiling of DNA is done on histone protein.
Histone protein is a positively charged protein that is made up of eight proteins so it is called histone octamer. Each histone has 2 copies of each protein that is H2A, H2B, H3, and H4.
DNA is negatively charged and histone protein is positively charged therefore DNA wraps around histone protein which causes the packaging of DNA. So the correct answer is histone protein.
I believe the polysaccharide that provides rigidity and strength in plants would be cellulose. As this is one of the essential components found in the cell wall of plant cells.
